Transmission system



Dec. 25, 1928. 1,696,261

5. H. WILLIAMS TRANSMISSION SYSTEM Filed Aug. 9, 1927 /A/ vzw 70R JA /a15. W/LL/AMJ I DRIVE) Patented Dec. 25, 1928.

UNITED STATES PATENT OFFICE.

SAMUEL B. WILLIAMS, OF BROOKLYN, NEW YORK, ASSIGNOR TO BELL TELEPHONELABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK.

TRANSMISSION SYSTEM.

Application filed August 9, 1927. Serial No. 211,678.

This invention relates to transmission systems and its object is toimprove systems for the distribution of programs to subscribers overphysical lines.

-A feature of the invention is a program distribution system in which asubscribers combined program indicating dial and switch operatingimpulse transmitter is arranged to rotate in a single direction tooperate a switch at central ofilce to select successive programs andalso to act once during each complete cycle to restore the centralofiice apparatus to normal.

In the drawing Fig. 1 illustrates a system including a subscribers line,and a portion of the central oilice equipment.

Fig. 2 shows the details of the impulse transmitter and programindicator located at the subscribers station.

By means of a specially constructed controlling dial, the subscriber toa broadcast service is enabled to select any deslred one of a number ofprograms and to receive such program on a receiving set at his premises.The subscribers controlling 1nstrument is arranged to transmit suchoperating impulses by rotating the control handle in a forwarddirection. This instrument also has a dial which serves as an index tothe particular program to which he is listening.

The construction of the combined impulse transmitter and'indicator dialis shown in detail in Fig. 2. A control handle 21 is attached to theshaft 25 to which is secured a ratchet wheel 26. A spring pressed pawi27 cooperates with the ratchet 26 to prevent the control handle 21 frombeing turned in the reverse direction. A pointer 22, secured to thehandle 21, moves over a dial 2G. The dial 20 has numerals or otherdesignations to indicate the different programs avaiiable.

The shaft 25 carries a yielding roller which moves over the serratedmen'iher 23 to hold the shaft 25 fir in any position to also carries anarm 2e, one end which is secured a coil spring of the s ring is fined toa secon The two shafts are held in nor: to each other hy means at pinsand 31.

The 35 carries an impuls wheel 4&3 which has a numhe .eth so ondir toeach position oi between the springs 32 and 33 and also a closurebetween the springs 33 and 34. Normally the springs 33 and 34.- remainopen.

In Fig. l is shown the subscribers receiver 1, and an amplifier 2. Thisset is connected through a repeating coil 3, to the line leading to thecentral office, and there terminating in a switch having the brushes 12,13, and 14:. The central ofiice switch has access to a number ofdifierent program equipments 16, 17 and 18.

The operation of the system will now be explained. Assume the subscriberwishes to listen to the program being sent from the equipment 18.Knowing the name or number onhis dial corresponding to this program, heseizes the handle 21 and rotates it until the pointer 22 reaches theproper position. During the rotation of the handle 21, the spring 29 istightened, which immediately causes the shaft 35 to rotate in the samedirection to bring the pin 31 back into engagement with the'stop pin 30.During rotation, the impulse springs 32 and 33 close and open acorresponding number of times/ On the first closure of the impulsesprings, a circuit is completed from batter through the winding of relay9, lower le t winding of coil 8, thence over the. lower side of theline, through the lower right winding of coil 3, springs 32 and 33, tothe upper right winding of coil 3 thence over the upper side or? theline, the upper left winding of coil. and the winding of relay 10 toground. With relays 9 and 13 operated, a circuit is closed from grouridthrough the front contacts of these clays, windings of siow rele 3erelay 11, ding of the stepping Y t 15, to but ery. On the next opening iaanet 15, which in s the hrushes l2,

M is or seen suc- 1e line, relay 9 releases and if oeeding impulse thebrushes of the switch are advanced until finally they stand on the setof terminals corr onding to the program distributing equlpment. 18.During the sending of the impulses, rela 11 remains operated, but afterthe impu es have been transmitted and an interval elapses,

this relay releases to complete a circuit trom the program set 18,through the brushes 12 and 13 and the contacts of said relay to theri%lethwindings of coil 8.

en the shaft 35 first starts to rotate, the governor weights 36 and 37raise the disc 38 to permit the spring 40 to move into engagement withthe spring 41. The sprin 40 and 41 serve to short-circuit the receivmgset 12, during the sendin of impulses. After the impulses have been sentand the shaft 35 comes to rest, springs 40 and 41 are again opened torender the receiving set efiective. The program is now received at thesubscribers station and he ma listen to. it until it is completed oruntil e desires to listen in on some other program or to disconnect hisline entirely from the central ofiice equipment. To listen in on another1pro am he merely continues to rotate the an le 21 until the pointer 22reaches the desired program.

In order to insure that the switch at the central ofiice is in, chronismwith the substation dial, the ial is so arranged that once perrevolution it causes the switch to restore to normal. As the controlhandle 21 is turned from the last program position toward the firstprogram position, the cam 43 presses the spring32 against the spring 33and the latter spring against the spring 34. The closure between thesesprings results in applying ound potential to both sides of the hne.This causes the operation of relay 9 and the release of relay 10. Withthis condition, a circuit is closed through the contact of relay 9, backcontact of relay 10, brush 14, and its associated terminals, contact ofmagnet 15, winding of relay 11, winding of magnet 15, to battery. Themagnet 15 interrupts its own circuit and steps the brushes 12, 13, and14 bacl: to normal position. The closure b the cam 43 is sufiicientl lonto permit to restore. A r t e cam 43 has passed under the spring 32, thespring drops into a notch openin the contacts. This notch may representt 'e normal position in which no 1plrograin is selected.

e room set at the subscribers sta-- tion has been shown in dia atic manner but it is to be'understo that it may be of any suitable What isclaims is:

1. In combination, a central oflice havan automatic switch thereinarranged to take a plurality of successive settin without releasing,circuits selectable by said e switch 'ments selectable b switch, asubscribers line leading to said switch, a transmitter atthe substationadjustable to any of a plurality of positions to send a correspon ingnumber of 1mpulses over the line, means responsive to said impulses toset said switch to select a desired circuit, a dial on the transmitterindicating the circuit selected, and means controlled by the transmitteronce during a complete operation for restoring the automatic switc 2. Incombination, a central oflice having an automatic switch therein,circuits selectable by said switch, a subscribers line leading to saidswitch, a transmitter at the substation adjustable to any of a pluralityof positions to send a corresponding number of impulses over the line,means for retaining the transmitter in its adjusted position; meansresponsive to said impulses to operate the switch to select one of saidcircuits, indicating means adjustable with the transmitter to indicatethe circuit selected, and means controlled by the transmitter duringeach complete cycle of operation to restore said automatic switch.

3. In combinatioma central ofiice having an automatic switch thereinarranged to take a plurality of successive settings without releasing, aplurali of program sending equipments selectab e by said switch, asubscribers line leading to said switch, a transmitter at the'substationadjustable to any of a plurality of positions to send a correspondingnumber of impulses over the line, means responsive to. said impulses toset said switch to select a desired program, a receiving set at thesubstation for receiving the selected program, an indicat' deviceadjustable with the transmitter to indicate the pro am being received,and means controlled y the transmitter for restoring said automaticswitch.

4. In combination, a central ofiice having an automatic switch thereinrogram distributing uipments selected by said automatic switc asubscribers line extending to said switch, a transmitter at thesubstation movable to any of a plurality of positions to send impulsesover the line, said transmitter remaining in the position last useduntil moved to a new'position, means responsiveto said impulses tooperate said switch to select a desired program, a dial on thetransmitter indicating1 the program selected, and means contro ed by thetransmitter during each cycle of operation for restoring the automaticswitch to normal.

5. In combination, a central office having an automatic switch therein,program equi said switch, a subscrib ers line, a transmitter at thesubstation rotatable in one direction only to successive positlons tosend over the line a number of impulses corresponding to the amount ofrotation, means responsive to the impulses for setting said switch toselect a desired equipment, an indicating device on said transmitter fordesignating the program selected, and means controlled by thetransmitter while moving from its last to its first position to restoresaid automatic switch to normal. v

6. In combination, a central oflice having an automatic switch therein,circuits selectable by said switch, a transmitter at the substationadjustable to different successive positions, a pair of impulse springsactuated by the transmitter during each adjustment to send acorresponding number of impulses over the line, means responsive, tosaid impulses to actuate said switch to select a desired circuit, a dialon saidtransmitter indicating the circuit selected, and a second set ofcontacts closed by the transmitter for restoring said automatic switchto normal.

7 In combination, a central ofiice having an automatic stepping switchtherein arranged to advance from one selective position to another,circuits selectable by said switch, a subscribers line leading to saidswitch, a transmitter at the substation adjustable to a plurality ofpositions to send a corresponding number of impulses over the line,means responsive to said impulses to set said switch to select a desiredcircuit, a dial on the transmitter indicating the circuit selected,

